Informal Workshop on Pollution Impacts of Secondary Roadways and their Mitigation

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Recommended Protocol for Evaluating the Location
of Sensitive Land Uses Adjacent to Major Roadways

Informal Workshop on Pollution Impacts of
Secondary Roadways and their Mitigation January
24, 2008
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ARBs Land Use and Air Quality Handbook

• In 1998, ARB identified diesel particulate matter
  as toxic air contaminant.
• In 2004, ARB recommended
• site new sensitive land uses at least 500 ft.
  from a freeway or other high traffic roadway
  (greater than 100,000k ADT)
• Based on So. Cal freeway studies
• At 500 ft., approx 70 percent reduction in PM
  concentrations
• suggested completing site-specific health risk
  assessment (HRA) if closer than 500 ft.

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ARBs Land Use and Air Quality Handbook Cover
Letter
To My Local Government Colleagues.
Land use decisions are a local government
responsibility. The Air Resources Boards role
is advisory and these recommendations do not
establish regulatory standards of any kind.
However, we hope that the information in this
document will be seriously considered by local
elected officials and land use agencies. We also
hope that this document will promote enhanced
communication between land use agencies and local
air pollution control agencies.
INTERIM CHAIRMAN, CALIFORNIA AIR RESOURCES BOARD
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ARBs Land Use and Air Quality Handbook
Key Health Findings - Reduced lung function in
children was associated with traffic density,
especially trucks, within 1,000 feet and the
association was strongest within 300 feet.
(Brunekreef, 1997) - Increased asthma
hospitalizations were associated with living
within 650 feet of heavy traffic and heavy truck
volume. (Lin, 2000) - Asthma symptoms increased
with proximity to roadways and the risk was
greatest within 300 feet. (Venn, 2001) - Asthma
and bronchitis symptoms in children were
associated with proximity to high traffic in a
San Francisco Bay Area community with good
overall regional air quality. (Kim, 2004) - A San
Diego study found increased medical visits in
children living within 550 feet of heavy traffic.
(English, 1999)
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ARBs Land Use and Air Quality Handbook
Figure 1-1 Decrease In Concentration of Freeway
Diesel PM Emissions With Distance
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The Need for a Protocol

• - Land use agencies began to see the ARB Handbook
  noted in CEQA comments.
• - There is a clear and compelling need for some
  type of viable guidance for developments near
  freeways.
• Local land use agencies approached SMAQMD for
  help
• can sensitive land uses be sited closer to major
  roadways in some cases without performing an
  expensive HRA?
• to ensure consistency and acceptability, how
  should air dispersion modeling and health risk
  assessments be performed?
• what mitigation is available?

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Protocol Objectives

• establishes a consistent cancer risk disclosure
  process that does not require a site-specific HRA
  for every project within 500 feet of a major
  roadway
• provides more information to planners and
  decision makers
• raises awareness of the need for mitigation
• local land use jurisdictions retain all
  authority and decide after considering all
  relevant factors whether the project is
  appropriate

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SMAQMD Outreach

• March 2006 met with ARB staff
• April 2006 local jurisdiction workshop
• July 2006 first draft released
• August 2006 public workshop, BIA presentation,
  SMAQMD Board as info
• October 2006 presentations to SACOGs AQ
  Committee, CAPCOA planning managers
• November 2006 BIA
• December 2006 training in CAL3QHCR, 5 month
  comment period closes
• January 2007 SMAQMD Board endorsement

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Screening Process
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The Protocol Screening Process
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Protocol Evaluation Criterion

• point at which a site specific HRA is recommended
• not a significance threshold, not an acceptable
  cancer risk
• set at a risk 70 percent reduction in risk from
  the worst case Sacramento scenario (mirrors ARB
  methodology)
• result 442 additional cancer cases per million
  people over a period of 70 years of exposure

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Example HRA Not Recommended

• receptor 100 feet downwind (north) from an
  east-west roadway
• 9,000 vehicles/hour- round up

• falls outside of shaded area, site specific HRA
  not recommended, but, report results in staff
  report or environmental document

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Example HRA Recommended

• receptor 27 feet downwind (east) from an
  north-south roadway
• 18,000 vehicles per hour

• project falls within shaded area, site specific
  health risk assessment is recommended, report
  results in staff report or environmental document

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Site-Specific Health Risk Assessment
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The CAL3QHCR Dispersion Model

• used in screening table development, recommended
  for site specific HRA
• EPA recommended
• line-source model
• text-based
• scrutinized in CAPCOA CEQA RA Subcommittee

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HRA Calculation

• highest annual average concentrations (ug/m3)
  used in conjunction with OEHHAs unit risk factor
  for DPM
• unit risk factor based on 24/7 exposure over a 70
  year timeframe
• OEHHA Hot Spots document the 70-year exposure
  timeframe is required as the basis for
  determining residential cancer risk
• most health protective timeframe available
• used by ARB in the Handbook

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SMAQMD Recommended Reporting Responsibility for
Site-Specific HRA

• risk for residence nearest to edge of travel lane
• risk at 10, 24, 50, 100, 300, 400 and 500 feet to
  show how risk drops off with distance
• modeling parameters

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Feedback on Protocol

• How did you come up with the 442/million
  criterion?
• Isnt the 442/million number a significance
  threshold?
• Why base the HRA on a 70 year exposure
  timeframe? Can we base it on 9 or 30 years?
• What about other kinds of health risk? Asthma?
• What can we do to mitigate?

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Current Mitigation Language

• exposure best reduced by increasing distance
  from the roadway
• potential measures could include electrostatic
  air filtering systems/vegetative barriers such as
  plantings of finely-needled trees to disperse and
  catch pollutants
• SMAQMD is, and will continue, actively
  supporting and encouraging research to identify
  effective and quantifiable mitigation measures
  that reduce exposure to air toxics from mobile
  sources

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Ongoing SMAQMD Mitigation Development and
Advocacy Efforts

• Research proposals
• to ARB 2007-2008
• cosponsored similar proposal to ARB for
  2008-2009, garnered support of many agencies
• AASHTO
• Funding UCD wind tunnel/vegetation studies
• SMAQMD LUTRAN staff works with project proponents
  to achieve vegetative plantings, suggest site
  redesign and ensure risk disclosure

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For Example

• In response to your request, the project
  applicant has agreed to the planting of
  fine-needled conifer trees in the freeway buffer
  area to mitigate air quality impacts. Total
  numbers, exact species, box-size at planting,
  spacing and placement will be determined in
  consultation with SMAQMD prior to adoption of a
  Tentative Map. Mitigation measure XX has been
  revised to reflect this commitment to plant
  fine-needled conifers in the freeway buffer and
  this revised measure is reflected in the final
  mitigation monitoring and reporting program to be
  approved by the City Council.

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Protocol V.2 Updates Currently in Progress

• The Protocol is an evolving document.
• expanding near-roadway health risks section, per
  recently published studies
• expanding mitigation section, per recently
  published studies and bibliography from this
  conference

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Questions?